Polymerization in aqueous emulsion



ments without adversely alloy containing nickel,

emulsion in' a glass vessel containing a Patented July 31, 1945 ropmarzarron lNAQUiiOUS EMULSION wuss L. Semen, Silver we. 01in, assignor to The B. F. Goodrich Pl a corporation of New York Application March 21, 1941,

NewYm-k, N. 1.,

No Drawing. i Q I SerialNo. 385,495 r 3 Claims. (Cl.

This invention relatrs tothe polymerization of unsaturated organic compounds in aqueous emulsion, and particularly to which the vessels in which such polymerizations are performed may advantageously be constructed.

' It is known that the vessel in which polymerizations in aqueous emulsion are conducted may profoundly aflect the course of the olymerization and the type of polymer obtained. When polymerizations are conducted in vessels made of many materials, there is formed a dep sit of polymer on the walls of the vessel which'reduces the heat-conductivity of the vessel and the yield of the desired type product. Other materials from which polymerizers might be constructed strongly inhibit polymerization reactions. It has further been found that certain metals which do not ordinarily adversely affect emulsion polymerizations cannot be employed after they are welded. -'Ihe diiiiculties coupled with the corrosion problems accompanying polymerizations in aqueous emulsions have made the selection of materials of construction for polymerizer very diflicult. Despite its fragility and poor heatconductivity, glass has been the material ordinarily selected (or this purpose.

I have discovered that an alloy containing 80% to 70% by weight of nickel, 15% to 20% of chromium, and 5% to of iron, is. an excellent material of construction for polymerizers. This alloy does not inhibitemulsion polymerization and it does not promote the formation of polymers upon its surface. Furthermore, this alloy; may be welded and subjected to other heat treataflecting its desirable properties. I

The method of this invention comprises polymerizing an unsaturated organic compoundemulsiiiedin water in a vessel in which the surfaces in contact with the emulsion are made of an chromium, and iron in the above-mentioned proportion. whole vessel maybe made of such an. alloy if desired,.a vessel constructed of Honor other comparatively inexpensive metal-lined with'the alloy is less expensive elect of an alloy containing about 74% of nickel,

18% of chromium, and 8% or iron upon emulsion a material from sulfonate, e

sions in a pH-range of from ten or over to three While the emulsion of vinyl V and equally satisfactory insofar as the eiiect of the vessel upon the polymerization polymerization, 75 parts of butadiene and 25; arts j. of acrylonitrile were copolymerized'in an aqueous strip of .nickel, 18% of chromium,

'employed,,there was very zation in an acid 260-845) the alloy. After five polymerizations, there were several spots of polymer on the glass, but none on the metal. The latices formed by the polymerizations were coagulated to form high quality synthetic rubbers which, when vulcanized, had tensile strengths oi 4000-5000 lbs/in. and elongations of, 550-700%. Welding the alloy did not aflect its behavior in during the second polymerization, and after the fourth polymerization there was a thick coating of adherent polymer on the metal.

In other polymerizations in which a vessel constructed of an alloy containing about 74% of and 8% of iron was little adherent polymer formed, and high quality synthetic rubbers were produced.

Polymerizations made of or lined with an alloy containing 80% to of nickel. 15% to 20% of chromium and 5% to 10% of iron in an acid, neutral or alkaline emulsion. If it is desired to eflfect the polymerimedium. salts oi hymolal bases such as the hydrochloride of diethylaminoethyloleylamide. trimethylcetyiammonium methyl sulfate,-etc., are ordinarily employed as emulsifying agents, while fattyacid soaps such as sodium oleate. sodium stearate; and sodiumpalmitate are employs to form alkaline emulsions. Hymolal sulfat s and aryl sulfonates such as sodium lauryl lfate, sodium isopropyl napthalene may be employed to form emulor less.

The polymerization of any unsaturated organic compound in aqueous emulsion may be advantageously eiiected in the presence of an alloy of thecomposition herein defined. As examples may be mentioned the polymerization in aqueous halides such as vinyl chloride, vinyl esters such as vinyl acetate. acrylic esters such as methyl methacrylate, oleflnes such as isobutylene, styrene, and vinyl naphthalene, conjugatefdienes such as butadiene, isoprene, chloroprene, and 2,3-dimethylbutadiene, and the copolymerization ganiccompounds such as vinylchloride and vinylacetate, butadiene and acrylonitrile, butadiene and methyl methacrylate, butadiene and styrene,

c. 1 His within the scope of the invention to em- "fi A 2,380,551

the emulsion polymerizamay be performed in vessels 01 two or more unsaturated or-.

ploy any or the catalysts, initiators, activators, modifiers or other material; which have been elsewhere described as being useful in emulsion polymerizations and which will not be specifically mentioned herein since their use forms no part of the invention} I claim:

l. The method which comprises polymerizing butadiene in aqueous emulsion in a vessel in which the surfaces contacting the emulsion during the polymerization are constructed of an slloy containing 80% to 70% of nickel, 15% to 20% of chromium, and 5% to 10% of iron.

2. The method which comprises copolymerisv structed of an alloy containing about 74% of nickel; 18% of chromium, and 8% of iron.

WALDO L. SEMON. 

